Section R. 285.641.5 - Liquid level-gauging devicesRule 5.
(1) A storage facility shall ensure that a storage container permits easy and safe measurement of the liquid level within the storage container. Liquid level gauging may be accomplished using any of the following: (b) See-through gradations.(e) Other approved means.(2) A storage facility shall ensure that exterior liquid level gauging devices are secured to protect against breakage and vandalism.(3) A storage facility shall ensure that a storage container which has external sight gauges has a lockable bottom valve and is locked closed when not in use.(4) A facility that is placed in service after the effective date of this rule shall immediately comply with this rule. A facility that is in service before the effective date of this rule has 2 years to comply with this rule.Mich. Admin. Code R. 285.641.5